Transport systems utilizing a track supplied with fluid under pressure

ABSTRACT

A track comprises a multiplicity of elemental nozzles controlled to discharge a layer of pressure fluid formed between the track and a load movable thereon when the presence of such load is detected, no pressure fluid being discharged in the absence of such load. This control is effected by means of a fluidic logic element responsive to a fluidic signal generated by a detector located on the track and sensitive to the presence of a load thereon.

United States Patent Thomas-Collignon Dec. 19, 1972 TRANSPORT SYSTEMS UTILIZING A TRACK SUPPLIED WITH FLUID UNDER PRESSURE Jean Charles Marie Thomas-Collignon, Chesnay, France Inventor:

Assignee: Bertin & Cie, Plaisir, France Filed: March 1, 1971 Appl. No.: 119,727

Foreign Application Priority Data Feb. 27, 1970 France ..7007206 US. Cl. ..302/3l, 137/815, 302/66 Int. Cl ..B65g 53/04 Field Of Search ..302/66, 31; 137/815 References Cited UNITED STATES PATENTS Baver et a1. ..l37/8l.5

FOREIGN PATENTS OR APPLICATIONS 644,113 2/1964 Belgium ..302/31 Primary Examiner-Richard E. Aegerter Assistant Examiner-H. Lane Attorney-Brufsky, Staas, Breiner & Halsey 57 ABSTRACT A track comprises a multiplicity of elemental nozzles controlled to discharge a layer of pressure fluid formed between the track and a load movable thereon when the presence of such load is detected, no pressure fluid being discharged in the absence of such load. This control is effected by means of a fluidic logic element responsive to a fluidic signal generated by a detector located on the track and sensitive to the presence of a load thereon.

12 Claims, 10 Drawing Figures SHEEI [1F 5 TRANSPORT SYSTEMS UTILIZING A TRACK SUPPLIED WITH FLUID UNDER PRESSURE The present invention relates to transport systems which include a track and a movable load capable of travelling along the same, a layer of fluid under pressure being delivered between the load and the track through openings connected by at least one conduit to a chamber forming part of the track.

In accordance with the invention, the track includes a chamber or enclosure delivering fluid-pressure through openings connected thereto through at least one conduit and is provided with conduit obturating means and with control means of the latter, said control means being formed in part at least by fluidic logic elements. Each control means is associated to a track element and is connected to means for detecting the presence of a movable load on that track element and downstream thereof.

The detection means may be formed by venting orifices capable of being partly obturated as a result of the passage of a movable load. The logic elements are formed by fluidic amplifiers comprising preferably monostable flip-flops.

The control means permit of admitting or cutting off the pressure-fluid which provides lift for the loads as they travel along; concurrently, a safety interval between consecutive loads is maintained and the rate of travel of the load is monitored.

The injection of pressure fluid beneath the load to be supported, which ensures safety and minimum expenditure of power, is enabled only when the load is located above the particular track element in question, a certain downstream distance along the track being devoid of all other loads.

The description which follows with reference to the accompanying non-limitative exemplary drawings will give a clear understanding of how the invention can be carried into practice.

In the drawings: 1

FIG. 1 is a schematic sectional view of a system according to the invention;

FIG. 2 shows in perspective with partial cutaway and on an enlarged scale the system of FIG. 1;

FIG. 3 is an alternative embodiment of FIG. 1;

FIG. 4 is a sectional view of an enlarged scale of another alternative embodiment;

FIG. 5 is a partial perspective view of the system shown in FIG. 4;

FIG. 6 is an alternative embodiment of FIG. 4;

FIG. 7 is a partial perspective view of the system shown in FIG. 6;

FIG. 8 is a diagrammatic perspective view of a system according to this invention;

FIG. 9 is an overall view of the system according to this invention; and

FIG. 10 is an alternative embodiment of FIG. 6.

Referring to FIG. 1, there is shown thereon a transport system such as a conveyor system, formed by a track 1 over which travels a pallet which may be a container or a passenger cabin driven by a motor (not shown). Beneath its chassis, the container includes chambers separated by a schematically illustrated seal 3. Preferably, the track 1 is hollow and is formed by a box member 8 which in cross-section is substantially of double-bottomed U-shape, the free vertical walls 4 and 5 of which guide the pallet while the horizontal surfaces 6 and 7 form the sealed enclosure 8 jointly with the extensions of walls 4 and 5. This enclosure is supplied with pressure fluid through a conduit (not shown). A monitoring distribution unit 11, portrayed schematically in FIG. I, is supplied with pressure fluid through a conduit 10 which supplies the control pressure.

FIG. 2 is a perspective view showing details of the unit 11 which is integrated into the upper track surface 6 and is devoid of moving parts. Upper panel 6 ispreferably formed of a plurality of superposed bonded plates, made for example of moulded plastic and embodying appropriate cutouts. The unit 11 consists of a vortex valve 19 which delivers the pressure fluid through a conduit 24 which debouches on to the track through orifices 25. Vortex valve 19 communicates with the pressurized track enclosure 8 through a duct 21 and a duct 22 and debouches on to track 1 through two supply orifices 25 via a duct 23 and conduit 24. Between vortex valve 19 and conduit 10 are provided means for detecting a pallet and for automatically controlling opening or shutting off of the pressure-fluid supply. These means are formed by two fluidic flipflops 12 and 15 and a distributor 30. On its upstream side, flip-flop 12 is connected to conduit 10 through a duct 31 and on its downstream side assures delivery either into duct 32 debouching tangentially into vortex valve 19 (in the event of absence of any control action), or into a venting orifice 18 on the track via a duct 33 (in the event of control action being applied). The upstream side of flip-flop 15 is connected to the pressurized track enclosure 8 through distributor 30, and on its downstream side to a venting track orifice 17 via a duct 34 and also to flip-flop 12 via a duct 35, which duct is utilized for controlling the flip-flop l2. Distributor 30 is connected to the pressurized track enclosure 8 through a duct 36 debouching at 13 and to a venting track orifice 14 through a duct 37.

The above-described arrangement is repeated at substantially regular intervals along the track. Interconnection between these several assemblies is provided, on the one hand, through the pressurized enclosure 8 extending along the whole length of the track, and on the other through pressure-fluid supplying conduit 10 and through a conduit 16 which communicates the distributor 30 with the flip-flop 15 of an assembly located at a predetermined downstream safeguarding distance that depends on the length of each pallet and on the rate of travel thereof.

For greater clarity, like parts in the next assembly will be designated by like reference numerals followed by a dash mark FIG. 8 schematically illustrates an assembly as described precedingly, while FIG. 9-portrays, along the length of the track, the manner of spacing a succession of assemblies which are interconnected in pairs, the safe spacing being chosen so that the first detector of pallet A be connected, for instance, to the tenth downstream detector which is the last detector of pallet B. The theory of operation of an installation as hereinbefore described is as follows:

The direction of travel of pallet 2 along track 1 is shown by the arrow F. A supply of pressure fluid is bled from enclosure 8 through duct 36 and vented on the track via distributor 30 and orifice 14 (provided that the latter is not obturated and consequently performs the function of a detector). The orifice 14 is so positioned along the track as to lie beneath the pallets as the same move along. If a pallet lies above orifice 14, the latter is blocked, for instance by the pallet element 20, whereby venting of the pressure fluid no longer occurs freely and the supply of fluid is routed to flip-flop 15. Should another pallet lie above the downstream orifice 14', at the corresponding safety distance, the pressure fluid bled through conduit 36' is routed through conduit 16 and actuates flip-flop 15. The supply of pressure fluid delivered through conduit 36 is diverted and discharged into the open air at 17 through duct 34.

If the'orifice 14 located at the safe downstream distance is not blocked by a pallet, the' supply of pressure fluid issuing from conduit 36 flows through flipflop 15 without being diverted and actuates flip-flop 12. The supply of high-pressure fluid which previously supplied vortex valve 19 tangentially through duct 32 is then injected into duct 33 and discharged into the open air through orifice 18. Being no longer supplied tangentially through duct 32, vortex valve 19 then delivers its full output into duct 23 and thereafter into the conduits 24, whereby the pressure fluid is delivered at the surface of the track through orifices 25 to provide lift for the pallet. After the pallet has moved past this particular assembly, the portion 20 no longer blocks orifice 14 and the pressure fluid is again channeled through duct 35 into the flip-flop 12 which accordingly supplies the vortex valve 19 tangentially through duct 32. Valve 19 is then unprimed and thereafter discharges only a very small fraction of pressure fluid into the surrounding atmosphere.

FIG. 3 shows an alternative embodiment in which two vortex valves have port directly through their associated orifices 23.

Reference is next had to FIGS. 4 and for a showing of another alternative embodiment of the invention, in which pressure fluid is caused to be delivered beneath pallet 2 by the opening of a valve 40 which is controlled and actuated by a fluidic circuit preferably integrated into the valve body.

FIG. 5 is a perspective showing of the arrangement of valve 40 in track 1. Valve 40 is contained in a housing 41 provided in the pressurized enclosure 8. At its center, housing 41 is provided with a hollow pivot 42 over which is placed the valve 40, the top of the latter being substantially hemispherical and its lower part being formed by cylindrical sleeve 43.

Upward movement of valve 4 inside housing 41 is limited by a protrusion 44, the space confined between valve 40 and housing 4.1 communicating with pressurized enclosure 8 via a duct 45. The portion of valve 40 located above protrusion 44 lies in the duct 23 which debouches on to the track via a conduit 24 and two orifices 25.

The internal passage 46 of pivot 42 communicates with pressure fluid supply conduit via a vortex valve 48 and a flip-flop 49. Communication between passage 46 and vortex valve 48 is through a duct 47, and a downstream branch 50 of flip-flop 49 is connected to tangential supply duct 51 of vortex valve 48 via a duct 52, the axial branch 68 of the vortex valve being vented at 66 through a duct 67. The second downstream branch 53 of flip-flop 49 is connected to a vent 55 on the track via a duct 54. The drive jet discharging nozzle 56 of flip-flop 49 is connected to pressure-fluid conduit 10 through a duct 57.

Further, the actuating branch 58 of flip-flop 49 forms one output of a flip-flop 59. Flip-flop 59 communicates with housing 41 via its drive jet delivering nozzle 60, and its other output is vented at 65 through a duct 64. The control conduit of said flip-flop associated to the control conduit-branch 58 is connected to nozzle 60 (i.e., to housing 41) via a diaphragm 63, and is vented at 61 via a duct 62.

Considering the direction of travel of pallet 2 to be that shown by arrow F, the theory of operation of the above-described arrangement is as follows:

Valve 40 is kept normally closed, that is to say pressed against protrusion 44 by the pressure of the fluid contained in pressurized enclosure 8. It is opened by direct venting of duct 46, whereupon valve 40 drops under gravity. Venting is effected through the central orifice 68 of vortex valve 48 which is vented at 66 via a duct 67.

The arrival of a pallet 2 upstream of the orifices 25 associated to valve 40 is detected by reason of the ensuing blocking of the discharge 61 by pallet element 20. This blocking effect activates flip-flop 49 to its downstream conduit-branch 53, causing the same to discharge into the open air at 55 and to thus cut off the tangential supply 51 to vortex valve 48. The duct 46 associated to valve 40 is then no longer pressurized, so that valve 40 drops on to pivot 42 and allows the pressure fluid contained in enclosure 8 to supply the orifices 25 via duct 45, housing 41, duct 23 and conduit 24.

As soon as the pallet has passed the assembly in question, orifice 61 is vented once more. Flip-flop 59 discharges into the open air at via its downstream branch 64, while flip-flop 49 discharges via its downstream branch 50 into duct 52 and supplies the vortex valve 48 tangentially through duct 51. Valve 48 discharges via duct 47 into duct 46, thereby thrusting valve 40 against protrusion 44 and communicating duct 46 with pressurized enclosure 8 via duct 45.

Reference is next had to FIGS. 6 and 7 for an alternative embodiment on that of FIGS. 4 and 5. The blocking effect on the duct 23' supplying pressure fluid to orifices 25 is obtained by means of a flexible mem brane 70 the rigid valve member 71 of which presses against protrusion 44 of duct 23.

The detection system is formed by a track vent 103 which communicates via a duct 102 with the way 101 of a distributor 100 having four ways 101, 104, 106 and 99. Way 106 comprises a flow limiting diaphragm 111 and communicates with pressurized enclosure 8 via ducts 107 and 108, housing 41 and duct 45. Way 99 controls an inhibitor 95 the second branch 97 of which debouches into the open atmosphere at 98 and the third branch 112 of which controls a flip-flop 90. The drive jet delivering nozzle 91 of flip-flop 90 communicates with pressurized enclosure 8 via a duct 109, duct 107, duct 108, housing 41 and duct 45. A downstream branch 93 of flip-flop 90 is vented at 94, and its second downstream branch 92 is the control means of a flip-flop 80. The drive jet delivering nozzle 78 of flip-flop 80 is supplied via conduit 10. A downstream branch of flip-flop is vented at 76 and its second downstream branch 74 communicates with the interior 72 of membrane 70 via a duct 73. The drive jet delivering nozzle 96 of inhibitor 95 is connected through a duct 110 to the distributor 100' located downstream of pallet 2 (the arrow F showing the direction of travel thereof). The fourth way 104 of distributor 100 is connected through a duct 105 to the drive nozzle 96 of'the inhibitor located upstream of pallet 2 (as determined by the direction of travel shown by the arrow F).

The theory of operation of the above-described system is as follows:

Rigid valve member 71 of membrane 70 is maintained closed in pressure contact against protrusion 44 through application of the control pressure for the pressure fluid delivered through conduit into chamber 72 via the branch 74 of flip-flop 80. Opening of valve 71 is caused by venting at 76 of chamber 72, with the drive jet reaching flip-flop 80 in response to a pressure applied in duct 77. When a pallet 2 overlies the calibrated leak 103, the pressure rises in distributor 100 and actuates flip-flop 90 provided that inhibitor 95 is not blocked through the arrival of another pallet, at a safe downstream distance, above the corresponding leak 103'. Since flip-flop 90 is controlled by the overpressure in branch 112, the fluid delivered through drive nozzle 91 is diverted into the downstream branch 92 and reaches flip-flop 80 via actuating duct 77. With the pressure fluid delivered, conduit 10 is connected to downstream branch 75 of flipflop 80 and escapes into the surrounding atmosphere at 76. Chamber 72 being no longer supplied via duct 74, the pressure therein decreases greatly and the overpressure prevailing in housing 41 acts on membrane 70 to lower the valve 71 whereby to allow the pressure fluid in enclosure 8 to discharge into the orifices 25 via duct 23 and conduit 24.

if a pallet 2 should be present at the safe downstream distance above the corresponding distributor 100', inhibitor 95 would remain blocked and continue to vent at 98, the mass flow being limited by diaphragm 111, thus preventing distributor 100 from acting on flip-flop 90.

It is thus possible to maintain the required intervals.

Because of the weight of the pallets to be conveyed, it may sometimes happen that the capsule form described in FIGS. 6 and 7 is unable to adapt to the load. FIG. 10 accordingly proposes a capsule of substantially cylindrical shape 115, formed by a bellows made of plastic for example, preferably reinforced with metallic trelliswork to enable it to withstand high pressures. Valve 116 and seat 117 may be made either of metal or plastic.

The various devices described in the present invention are positioned along the track in accordance with the same safeguarding arrangements described with reference to FIGS. 8 and 9. The valve delivering pressure fluid can consequently be active only provided that its companion valve at the safeguarding distance away is free of any load.

It goes without saying that many changes and substitutions of parts may be made in the above-described exemplary embodiments without departing from the scope of the invention as set forth in the appended claims.

Iclaim:

1. A method of controlling obturation of a fluid supply conduit connected to orifices opening on a track for conveying ground effect loads with the interposition of a fluid layer between a given section of said track and a movable load located in registry with said track section, said fluid supply conduit extending within and all along said track, said method comprising the steps of sensing the state of presence or absence of said load at such location, generating accordingly a fluidic signalrepresentative of said state, applying said fluidic signal as pilot signal to govern the operative condition of a twin-output'fluidic logic element, selectively venting said fluidic logic element through one of the outputs thereof and putting the obturation of said fluid supply conduit under the control of said fluidic logic element through the other output thereof.

2. Method as claimed in claim 1, comprising the further steps of sensing the state of presence or absence of a load located in registry with another section of said track at a distance from said given section, generating accordingly another fluidic signal representative of said last-mentioned state, and applying said other fluidic signal as further pilot signal to govern said operative condition of said fluidic logic element.

3. Method as claimed in claim 2, wherein said other track section is selected at a distance ahead of said given track section with respect to the displacement direction of said loads along said track.

4. A ground effect transport system of the kind comprising a track for the conveyance therealong of movable loads floated on an interposed layer of fluid discharged from nozzles opening on said track and supplied with pressure fluid from a conduit extending within and all along said track, means for detecting the presence or absence state of a load thereon and generating accordingly a fluidic signal representative of said state, and obturator means under the control of said fluidic signal for controlling fluid supply to said nozzles, wherein the improvement comprises a fluidic logic element fitted between said detecting means and said obturator means and comprising at least one fluidic flip-flop arranged to be piloted by said fluidic signal and having an output adapted to deliver a power jet for the control of said obturator means, and a further output opening into the atmosphere, the two outputs being in branched relationship.

5. System as claimed in claim 4, wherein said fluidic logic element further comprises a control passage associated with said further output, a distributor under the control of said detecting means for delivering pressure fluid to said control passage, and a pressure fluid source connected to said distributor, the arrangement being such that, upon detection of the presence of a load by said detecting means, pressure fluid is delivered to said control passage to deflect said power jet towards the corresponding output whereby to open said obturator means.

6. System as claimed in claim 5, further comprising a second load detecting means at a distance from the former-mentioned load detecting means, a second fluidic flip-flop having a power jet producing nozzle connected to said distributor, an output which is said control passage and another output opening into the atmosphere, a further control passage associated with said other output, and a further pressure fluid distributor under the control of said second load detecting l060ll 0066 means for delivering pressure fluid to said further control passage, the arrangement being such that, upon detection of the presence of a load by said second detecting means, pressure fluid is delivered .to said further control passage of said second flip-flop to deflect the power jet produced by said nozzle thereof towards said other output opening into the atmosphere, whereby said former-mentioned flip-flop has its power jet left unaffected.

7. System as claimed in claim 4, comprising a first fluidic flip-flop having an output opening into the atmosphere, a control passage under the control of said detecting means and supplied with pressure fluid, and another output, a second fluidic flip-flop having a control passage which is said other output of said first flipflop, an output opening into the atmosphere, and another output, and a vortex valve having a vent under the control of a further load detecting means and a radial output conduit adapted to deliver motive fluid to actuate said obturating means.

8. System as claimed in claim 4, further comprising a first distributor with a first branch opening into the atmosphere, a second branch having a power nozzle supplied with pressure fluid, a third branch connected to an upstream track section, and a fourth branch, a second like distributor with four branches the third of which is connected to a downstream track section, an inhibitor circuit'to which said fourth branch of said first distributor leads and which is connected to said third branch of said second distributor, said inhibitor circuit comprising a way which opens into the atmosphere and another way, a first fluidic flip-flop under the control of said other way of said inhibitor circuit and having an output opening into the atmosphere and another output, and a second fluidic flip-flop having a control passage which is said other output of said first flip-flop, an output opening into the atmosphere and another output connected to said obturator means.

9. System as claimed in claim 4, wherein said obturator means comprise vortex type fluid valves respectively connected tangentially to a flip-flop output adapted to deliver a power jet for the control of said obturator means.

10. System as claimed in claim 4, wherein said obturator means comprise free type valve members having one face cooperating with a valve seat and another face exposed to the power jet delivered by a respective flipflop output.

1 1. System as claimed in claim 4, wherein said fluidic logic element is integrated into said track and is purely static, having no movable part.

12. System as claimed in claim 4, wherein said fluidic logic element and said obturator means are incorporated into a box-like unit associated with the track surface. 

1. A method of controlling obturation of a fluid supply conduit connected to orifices opening on a track for conveying ground effect loads with the interposition of a fluid layer between a given section of said track and a movable load located in registry with said track section, said fluid supply conduit extending within and all along said track, said method comprising the steps of sensing the state of presence or absence of said load at such location, generating accordingly a fluidic signal representative of said state, applying said fluidic signal as pilot signal to govern the operative condition of a twin-output fluidic logic element, selectively venting said fluidic logic element through one of the outputs thereof and putting the obturation of said fluid supply conduit under the control of said fluidic logic element through the other output thereof.
 2. Method as claimed in claim 1, comprising the further steps of sensing the state of presence or absence of a load located in registry with another section of said track at a distance from said given section, generating accordingly another fluidic signal representative of said last-mentioned state, and applying said other fluidic signal as further pilot signal to govern said operative condition of said fluidic logic element.
 3. Method as claimed in claim 2, wherein said other track section is selected at a distance ahead of said given track section with respect to the displacement direction of said loads along said track.
 4. A ground effect transport system of the kind comprising a track for the conveyance therealong of movable loads floated on an interposed layer of fluid discharged from nozzles opening on said track and supplied with pressure fluid from a conduit extending within and all along said track, means for detecting the presence or absence state of a load thereon and generating accordingly a fluidic signal representative of said state, and obturator means under the control of said fluidic signal for controlling fluid supply to said nozzles, wherein the improvement comprises a fluidic logic element fitted between said detecting means and said obturator means and comprising at least one fluidic flip-flop arranged to be piloted by said fluidic signal and having an output adapted to deliver a power jet for the control of said obturator means, and a further output opening into the atmosphere, the two outputs being in branched relationship.
 5. System as claimed in claim 4, wherein said fluidic logic element further comprises a control passage associated with said further output, a distributor under the control of said detecting means for deliVering pressure fluid to said control passage, and a pressure fluid source connected to said distributor, the arrangement being such that, upon detection of the presence of a load by said detecting means, pressure fluid is delivered to said control passage to deflect said power jet towards the corresponding output whereby to open said obturator means.
 6. System as claimed in claim 5, further comprising a second load detecting means at a distance from the former-mentioned load detecting means, a second fluidic flip-flop having a power jet producing nozzle connected to said distributor, an output which is said control passage and another output opening into the atmosphere, a further control passage associated with said other output, and a further pressure fluid distributor under the control of said second load detecting means for delivering pressure fluid to said further control passage, the arrangement being such that, upon detection of the presence of a load by said second detecting means, pressure fluid is delivered to said further control passage of said second flip-flop to deflect the power jet produced by said nozzle thereof towards said other output opening into the atmosphere, whereby said former-mentioned flip-flop has its power jet left unaffected.
 7. System as claimed in claim 4, comprising a first fluidic flip-flop having an output opening into the atmosphere, a control passage under the control of said detecting means and supplied with pressure fluid, and another output, a second fluidic flip-flop having a control passage which is said other output of said first flip-flop, an output opening into the atmosphere, and another output, and a vortex valve having a vent under the control of a further load detecting means and a radial output conduit adapted to deliver motive fluid to actuate said obturating means.
 8. System as claimed in claim 4, further comprising a first distributor with a first branch opening into the atmosphere, a second branch having a power nozzle supplied with pressure fluid, a third branch connected to an upstream track section, and a fourth branch, a second like distributor with four branches the third of which is connected to a downstream track section, an inhibitor circuit to which said fourth branch of said first distributor leads and which is connected to said third branch of said second distributor, said inhibitor circuit comprising a way which opens into the atmosphere and another way, a first fluidic flip-flop under the control of said other way of said inhibitor circuit and having an output opening into the atmosphere and another output, and a second fluidic flip-flop having a control passage which is said other output of said first flip-flop, an output opening into the atmosphere and another output connected to said obturator means.
 9. System as claimed in claim 4, wherein said obturator means comprise vortex type fluid valves respectively connected tangentially to a flip-flop output adapted to deliver a power jet for the control of said obturator means.
 10. System as claimed in claim 4, wherein said obturator means comprise free type valve members having one face cooperating with a valve seat and another face exposed to the power jet delivered by a respective flip-flop output.
 11. System as claimed in claim 4, wherein said fluidic logic element is integrated into said track and is purely static, having no movable part.
 12. System as claimed in claim 4, wherein said fluidic logic element and said obturator means are incorporated into a box-like unit associated with the track surface. 